ESR Meter is an irreplaceable tool for troubleshooting and repairing electronic equipment by determining performance and health of electrolytic capacitors. Unlike other ESR Meters that only measure ESR value this one measures capacitor's ESR value as well as its capacitance all at the same time. Additionally, ESR Meter also tests and identifies PINs of all transistors such as Bipolar (NPN, PNP), FETs, MOSFETs (N-Channel, P-Channel, enhancement-mode and depletion-mode MOSFETs), Thyristors, SCRs and Triacs. Tests and identifies PINs and voltage of diodes, dual diodes, varicap diodes (and their capacity), zener diodes (test voltage up to 5V) and LEDs. It measures resistance of resistors, power resistors, coils starting from just 0.1Ω up to 20MΩ.

What is ESR?

"ESR" stands for equivalent series resistance. ESR is one of the characteristics that defines the performance of an electrolytic capacitor. Low ESR is highly desirable in a capacitor as any ripple current through the capacitor causes the capacitor to heat up due to the resistive loses. This heating accelerates the demise of the capacitor by drying out the electrolyte at an ever increasing rate. Over the lifetime of a capacitor, it is not uncommon for the ESR to increase by a factor of 10 to 30 times or even go open circuit. Typical lifetime ratings for electrolytics are 2000-15000 hours and are very dependent on ambient operating temperature. As the ESR increases, the filtering operation of the capacitor becomes impaired and eventually the circuit fails to operate correctly.

Electrolytic capacitors are by far the electronic parts that suffer aging soonest. If you have any electronic equipment that over the years has degraded its performance, developed quirks, sometimes ending in complete failure, the chances are good that one or more electrolytic capacitors inside it have degraded, causing the problem. Electrolytic capacitors age in several ways: They can become electrically leaky, causing a DC current through them that can make them blow up. They can shift in capacitance value. But the most common way they degrade, by far, is by unduly increasing their equivalent series resistance, which is the undesired internal resistance that appears in series with the wanted capacitance at a given frequency.

ESR can generally give us a better indication about the health of a capacitor. As an electrolytic capacitor begins to dry up the ESR is affected much more than the capacitance. A capacitor with a correct capacitance value but abnormally high ESR is well on its way to failure because the high ESR will cause more heat build up which will end up destroying the capacitor. If the capacitor has already lost a fraction of its initial capacitance value, the ESR will normally have increased by a large factor.

ESR resistance value of a good capacitor depends on many factors, capacitance value is the most relevant. The higher the capacitance the lower the ESR. In any capacitor of over a few tens of uF it would be a fraction of ohm and even in the smallest electrolytic capacitors it would not be more than a few ohm. For a given capacitance the next most relevant factor is the quality of the design and manufacturing. Some capacitors are designed and built to have much lower ESR than others. After those two factors there are others which affect nominal voltage (for the same capacitor type/series, the higher the nominal voltage the higher the ESR) and temperature rating (the higher the temperature rating the higher the ESR).

ESR Reference Values

When measuring electrolytic capacitors use the following table to determine quality of measured capacitor. It is normal that capacitors with smaller capacity (1uF – 47uF) usually have higher ESR value while capacitors with higher capacity will have lower ESR value.

Capacitance

Capacitor Quality

uF

Very high

High

Normal

Low

Very low

1.0

2.000

5.000

12.500

31.250

78.125

2.2

1.125

2.812

7.030

17.574

43.936

4.7

0.646

1.616

4.039

10.098

25.244

10

0.372

0.931

2.328

5.819

14.548

22

0.209

0.524

1.309

3.273

8.181

47

0.120

0.301

0.752

1.880

4.701

100

0.069

0.173

0.433

1.084

2.709

220

0.039

0.097

0.244

0.609

1.523

470

0.022

0.056

0.140

0.350

0.875

1000

0.013

0.032

0.081

0.202

0.504

2200

0.007

0.018

0.045

0.113

0.284

4700

0.004

0.010

0.026

0.065

0.163

10000

0.002

0.006

0.015

0.038

0.094

Powering Up ESR Meter

1. Connect ESR Meter to 7-16V power source / 9V battery

2. Connect component to be tested to input terminals (1/2/3)

3. Press “TEST” button

4. Component value will be displayed on LCD display

ESR Meter - Measuring Capacitors

ESR Meter - Testing Transistors

ESR Meter - Measuring Resistors

ESR Meter - Testing Diodes and LEDs

Adjusting LCD Contrast

If square blocks are visible on LCD display it might be necessary to readjust LCD contrast settings. Please detach 16x2 LCD Display from the main PCB board and adjust blue trimmer (102) counterclockwise. If text is to light adjust trimmer clockwise. Reconnect LCD display and power ESR Meter to make sure that LCD display has sharpest text without displaying square blocks in the background.

ESR Meter kit

You can purchase a complete premium quality ESR Meter / Transistor Tester kit at Electronic-DIY store please see the link for more details.